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  2. List of human cell types - Wikipedia

    en.wikipedia.org/wiki/List_of_human_cell_types

    The main cellular components of the human body by count [6] Cell type % cell count: Erythrocytes (red blood cells) 84.0 Platelets: 4.9 Bone marrow cells 2.5 Vascular endothelial cells: 2.1 Lymphocytes: 1.5 Hepatocytes: 0.8 Neurons and glia: 0.6 Bronchial endothelial cells: 0.5 Epidermal cells: 0.5 Respiratory interstitial cells: 0.5 Adipocytes ...

  3. Composition of the human body - Wikipedia

    en.wikipedia.org/wiki/Composition_of_the_human_body

    The main elements that comprise the human body (including water) can be summarized as CHNOPS. Element Symbol percent mass percent atoms Oxygen O 65.0 24.0 Carbon C 18.5 12.0 Hydrogen H 9.5 62.0 Nitrogen N 2.6 1.1 Calcium Ca 1.3 0.22 Phosphorus P 0.6 0.22 Sulfur S 0.3 0.038 Potassium K 0.2 0.03 Sodium Na 0.2 0.037 Chlorine Cl 0.2 0.024 Magnesium Mg

  4. Ultimopharyngeal body - Wikipedia

    en.wikipedia.org/wiki/Ultimopharyngeal_body

    [1] [2] It is technically from the fifth pharyngeal pouch, but this is rudimentary and merges with the fourth. [2] It develops into the parafollicular cells of the thyroid. [2] The cells that give rise to the parafollicular cells are derivatives of endoderm. [3] Endoderm cells migrate and associate with the ultimopharyngeal body during development.

  5. Cell (biology) - Wikipedia

    en.wikipedia.org/wiki/Cell_(biology)

    Ribosomes can be found either floating freely or bound to a membrane (the rough endoplasmatic reticulum in eukaryotes, or the cell membrane in prokaryotes). [11] Plastids: Plastid are membrane-bound organelle generally found in plant cells and euglenoids and contain specific pigments, thus affecting the colour of the plant and organism. And ...

  6. Organ (biology) - Wikipedia

    en.wikipedia.org/wiki/Organ_(biology)

    In a multicellular organism, an organ is a collection of tissues joined in a structural unit to serve a common function. [1] In the hierarchy of life, an organ lies between tissue and an organ system. Tissues are formed from same type cells to act together in a function. Tissues of different types combine to form an organ which has a specific ...

  7. Biological roles of the elements - Wikipedia

    en.wikipedia.org/wiki/Biological_roles_of_the...

    A large fraction of the chemical elements that occur naturally on the Earth's surface are essential to the structure and metabolism of living things. Four of these elements (hydrogen, carbon, nitrogen, and oxygen) are essential to every living thing and collectively make up 99% of the mass of protoplasm. [1]

  8. Tissue (biology) - Wikipedia

    en.wikipedia.org/wiki/Tissue_(biology)

    The cells of the body's surface form the outer layer of skin. Inside the body, epithelial cells form the lining of the mouth and alimentary canal and protect these organs. Epithelial tissues help in the elimination of waste. Epithelial tissues secrete enzymes and/or hormones in the form of glands. Some epithelial tissue perform secretory functions.

  9. Cerebrum - Wikipedia

    en.wikipedia.org/wiki/Cerebrum

    The cerebrum is a major part of the brain, controlling emotions, hearing, vision, personality and much more. It controls all precision of voluntary actions, and it functions as the center of sensory perception, memory, thoughts and judgement; the cerebrum also functions as the center of voluntary motor activities.